Research On Spatial Mechanical Behavior Of Twin-box Single-cell PC Box Girder With Corrugated Steel Webs

The Box Girder Bridge with Corrugated Steel Web is a new kind of steel-concretecomposite bridges; Shenzhen Nanshan Bridge being designed is the largest span of thistype.Because of large width, the bridge uses a twin-box single-cell cross-section which isconnected with the bridge deck and beams. In order to explore the structure of space-forceperformance and validate its applicability in design,t Taking Nanshan Bridge as the projectbackground, model tests of twin-box single-cell box girder with corrugated steel webswere conducted.The commercial finite element software, ABAQUS is used for modelanalysis. Based on test result and model analysis, the main research results are described asfollows：(1) the single-cell mechanical properties of the twin-box single-cell box girder withcorrugated steel webs is similar to the single-box single-cell’s; the distribution oflongitudinal strains along the depth of cross section satisfies the plane section Assumptionin elastic phase.(2) The commercial Finite Element Software, ABAQUS, is adopted to analyze thebox-girder with corrugated steel webs, which is validated through the experimental resultsin this thesis. Taking the secondary transverse beam, which is relevant to the integrity ofthe test model, as the parameters, the results show that the secondary transverse beamcould improve the force status of the top plate, however does not contribute to enhance theintegrity of the box girder. On this basis, the effect of two new kinds of transverse beam(major beam and major beam with secondary beam) on the mechanical characteristics ofthe test girder is discussed. The result shows that the form of major beam with secondarybeam not only effectively enhances the integrity of the girder, but also improves stress stateof the girder’s top plate and bottom plate without considerable increase of girder’s selfweight.(3) With the Finite Element Method which has been verified by the experiment,Nanshan Bridge’s spatial force characteristic has been discussed. The result shows that mechanical behavior of twin-box single-celll girder with corrugated steel webs was similarto that of the test girder. The cross beam (with deck slab) with rib in inner box wasanalyzed under live load. The analysis results indicate that concrete crack, shearingstrength, and integrity meet the requirements and large tensile force exists between twoboxes which is hard to improve by reinforcement. So, deck slab with rib barely act astransverse beam.(4) The transverse beam of Nanshan Bridge was redesigned using two styles whichhave been discussed in test model. And the mechanical characteristics of the originaldesign was compared. The results showed that addition of large beams form a small beamscan not only effectively enhance the integrity of the two boxes at the same time can be agood bridge panel to improve the mechanical properties. Because of advantages delineatedabove, double-box-single cell with corrugated steel web PC box girder shows goodresemblance for large span bridges.